1. Field of the Invention
This invention relates to positive clutch mechanisms, and particularly a clutch mechanism in which the driven shaft is maintained in an indexed position when the mechanism is disengaged, and in which the driven shaft is re-engaged from the indexing position in synchronization with the drive shaft.
2. Description of the Prior Art
Various drive mechanisms are known which include positive clutches which permit the operation of the mechanism to be disengaged when necessary. These clutches may include, for example, various types of engaging means whereby the clutch is engaged to rotate a driven shaft from a drive shaft upon the actuation of a lever, a pneumatic cylinder, or an electronic switch.
Among the features of the known clutch mechanisms may be the positioning of the driven shaft in a predetermined indexing position upon disengagement of the clutch. When the clutch is re-engaged, the driven shaft begins rotating again from the indexing position immediately upon actuation of the mechanism. Another feature of existing clutch mechanisms is the ability to begin actuation of the mechanism at a predetermined point in the rotation of the drive shaft or in the sequencing of other apparatus so that the driven shaft will rotate in synchronization with drive shaft or sequencing apparatus.
Heretofore, prior art clutch mechanisms have not included both of these capabilities. Clutch mechanisms known to the present inventor have not been capable of mechanically holding the driven shaft in a predetermined indexing position upon disengagement of the clutch mechanism, and upon re-engagement of the clutch mechanism beginning the rotation of the driven shaft from this indexing position at a point of time after re-engagement of the clutch mechanism so that the driven shaft will rotate in the same synchronization with drive shaft or sequential apparatus, as before disengagement.
The need for such an indexing clutch mechanism which incorporates both capabilities has been found in apparatus which changes the incremental length between articles moving in an automatic assembly. In such an apparatus, the articles enter a feed control means in close proximity to each other and are separated and driven at a greater speed so that the articles are thereafter moving at a greater speed and separated by a greater distance. A rotating stopping device, such as a star wheel, is used to control the feed of the articles, and this device must be rotating in synchronization with the indexing mechanisms downstream, so that each article is placed in the proper position and separated by the proper distance. If it is necessary to halt the feed of articles to the apparatus, the rotating stopping device must be halted in a predetermined indexing position so that the articles entering the apparatus will be maintained in a position in which the assembly can be restarted. When the feed of articles to the apparatus is restarted, the rotating device must begin rotation from its indexing position exactly in synchronization with the downstream mechanisms.
Clutch mechanisms known heretofore have not been found suitable for the purposes of maintaining synchronization between a driven shaft on which a rotating stopping device may be mounted and a drive shaft which may be connected to the downstream mechanisms, assuring placement of the drive shaft in a preset indexing position upon disengagement of the clutch mechanism, and maintaining synchronization after re-engagement of the mechanism.